dagger — Phase 2 DoD extractor (scratch-trained 3/4/5-speaker curriculum, LibriMix)

• Repo / code: https://github.com/RohanBanerjee88/dagger
• Training config: configs/phase2/dod/phase2_librimix_curriculum_3_4_5_train_scratch.yaml (--system proposed). Multi-depth curriculum: batches interleaved from three loaders (n_src 3, 4, 5; 800 scheduled-placement Libri3Mix train-360 scenes each, 2400 total), 10 epochs, batch 4, lr 3e-4, grad_clip 50, one T4, ~6.5 h. "Curriculum" here means several overlap depths in one run, not easy-to-hard ordering.
• Eval configs: configs/phase2/dod/phase2_librimix_{3,4,5}spk_eval_scratch.yaml — 150 test scenes each, oracle diarization, tag scratch345clip50.
• Sample rate: 8 kHz.
• Speaker counts seen in training: 3, 4, 5 (recorded in the checkpoint as trained_n_src).

Results

• Ordering, 9 of 9 slices: coarse_to_fine > gated_deflation > ungated_deflation at every overlap depth 2–5 across all three eval sets. Holds on both scratch checkpoints (18/18) and on every warm-started checkpoint before them.
• Accumulation (ungated_deflation, SI-SDR vs. number of prior estimates subtracted into the residual; m=5 at depth 5, n=150 per level): -4.97 → -5.89 → -6.31 → -7.00 → -6.78, -1.81 dB total, monotone through the body of the chain. The terminal step is the one-and-rest endpoint and flattens — a benign case of Theorem 2's ‖E_m‖ ≤ m·ε upper bound.
• Absolute SI-SDR (no_recursion, deepest depth per set): 3spk -1.29, 4spk -3.47, 5spk -4.87 dB. Negative at depths 4–5 for every system, including the one with no deflation logic — this is the extractor's operating point under a small training budget (~2,000 steps at n_src=3 vs. Phase 1's 15,000), not the reconstruction strategy.

Caveats

• The ordering is checkpoint-robust; the accumulation magnitude is not. It measures ~1.8 dB on scratch-trained curriculum checkpoints (replicated twice, agreeing to 0.08 dB per level) and 5.30 dB on the earlier warm-started chain trained on the same curriculum recipe. Quote the magnitude as a range with the checkpoint named.
• Oracle diarization only. Real-diarization robustness is Phase 3 and not yet measured.
• Synthetic 8 kHz LibriMix (English read speech, hard boundaries, no reverb). Real-corpora numbers are Phase 4.
• Set refine.rounds: 0 unless you have contaminated enrollment. Embedding refinement was measured net-harmful under clean enrollment (-0.07 to -0.41 dB across 9 slices, gate healthy).
• Research artifact for reproducing the Phase 2 experiment — not a production separation model.

Files

• proposed_librimix_curriculum_3_4_5_scratch_clip50.pt — a torch.save dict with state_dict, model_config, system, trained_n_src. The architecture must match exactly or load_state_dict raises: hidden_channels 64, n_blocks 6, n_fft 256, hop_length 64, n_heads 4, n_tokens 8, cross_attn_blocks 6.

License

Usage